AN agreement sealed by leaders of the G8 nations meeting in Northern Ireland can "rewrite the rules" on tax and transparency to benefit countries across the world, David Cameron said today.

The Lough Erne Declaration - signed by the UK, US, Germany, France, Italy, Canada, Japan and Russia - vows to "fight the scourge of tax evasion" by ensuring automatic exchange of tax information and changing the rules to stop multinational companies shifting profits across borders to avoid paying their fair share.

Mr Cameron said the declaration would support nations including the poorest in the world and would help ensure "proper tax justice".

Speaking at a press conference in the resort, he said: "We agreed a Lough Erne declaration that has the potential to rewrite the rules on tax and transparency for the benefit of countries right across the world, including the poorest countries in the world.

"We have commissioned a new international mechanism that will identify where multinational companies are earning their profits and paying their taxes so we can track and expose those who aren't paying their fair share."

He said the new tool would help ensure "proper tax justice in our world".

But the 10-point document, released after two days of talks at Lough Erne, falls short of the demands of anti-poverty campaigners, who want the developing world included in the new arrangements from the start and have called for tax information to be made available to all on public registers.

The declaration says only that developing countries "should have the information and capacity to collect the taxes owed them", rather than guaranteeing them automatic access to the information.

And it says only that "tax collectors and law enforcers" should have access to information about the ultimate owners of companies, leaving it to individual G8 countries to decide whether to make the information public.

The White House said it would leave the decision to individual US states, while Chancellor George Osborne said the UK was "open" to the idea of public registers and is consulting on the issue.